This invention relates to medical apparatus, and more particularly to apparatus for use in making anastomotic connections between tubular body fluid conduits in a patient.
There are many medical procedures in which it is necessary to make an anastomotic connection between two tubular body fluid conduits in a patient. An anastomotic connection (or anastomosis) is a connection which allows body fluid flow between the lumen of the two conduits that are connected, preferably without allowing body fluid to leak out of the conduits at the location of the connection. As just one example of a procedure in which an anastomosis is needed, in order to bypass an obstruction in a patient's coronary artery, a tubular graft supplied with aortic blood may be connected via an anastomosis to the coronary artery downstream from the obstruction. The anastomosis may be between the end of the graft and an aperture in the side wall of the coronary artery (a so-called end-to-side anastomosis), or the anastomosis may be between an aperture in the side wall of the graft and an aperture in the side wall of the coronary artery (a so-called side-to-side anastomosis (e.g., as in published Patent Cooperation Treaty (“PCT”) patent application WO 98/16161, which is hereby incorporated by reference herein in its entirety)). The graft may be natural conduit, artificial conduit, or a combination of natural and artificial conduits. If natural conduit is used, it may be wholly or partly relocated from elsewhere in the patient (e.g., wholly relocated saphenous vein or partly relocated internal mammary artery). Alternatively, no relocation of the graft may be needed (e.g., as in above-mentioned application WO 98/16161 in which a length of vein on the heart becomes a “graft” around an obstruction in an immediately adjacent coronary artery). More than one anastomosis may be needed. For example, a second anastomosis may be needed between an upstream portion of the graft conduit and the aorta or the coronary artery upstream from the obstruction in that artery. Again, this second anastomosis may be either an end-to-side anastomosis or (as shown, for example, in above-mentioned application WO 98/16161) a side-to-side anastomosis. Alternatively, no second, upstream anastomosis may be required at all (e.g., if the graft is an only-partly-relocated internal mammary artery).
The currently most common technique for making an anastomosis is to manually suture the two tubular body fluid conduits together around an opening between them. Manual suturing is difficult and time-consuming, and the quality of the anastomosis that results is highly dependent on the skill of the person doing the suturing. In the case of coronary artery bypass procedures, one source of difficulty for suturing of an anastomosis may be motion of the heart. There is also increasing interest in procedures which are less invasive or even minimally invasive. Such procedures have potentially important advantages for patients, but they may increase the difficulty of performing manual suturing of an anastomosis by reducing or limiting access to the site within the patient at which the anastomosis must be made. Various examples of such less invasive or minimally invasive procedures are shown in above-mentioned application WO 98/16161, Goldsteen et al. U.S. Pat. No. 5,976,178, Sullivan et al. U.S. Pat. No. 6,120,432, published PCT patent application WO 98/55027, and Berg et al. U.S. patent application Ser. No. 09/187,364, filed Nov. 6, 1998, all of which are hereby incorporated by reference herein in their entireties.
In the case of making a conventional end-to-side anastomosis between a vein graft and the coronary artery, there are additional difficulties which may arise. First, the relative sizes of the coronary artery and the vein graft are different. For example, the coronary artery may typically have an inner diameter of about 1.0 to 3.0 mm, whereas a vein graft, such as the saphenous vein, may typically have an inner diameter of about 4 to 8 mm. This discrepancy between vessel diameters, i.e., a “caliber mismatch,” may present a challenge to the physician to match the end of the relatively larger vein graft to an aperture in the side wall of the relatively smaller coronary artery. The resulting quality and amount of flow between the vein graft and the coronary artery, along with the provision of an effective hemodynamic seal between the two conduits, is often dependent upon the physician's skill in making an effective junction between the two conduits.
Second, conventional end-to-side anastomosis typically joins the graft conduit to the coronary artery at an angle with respect to the lumen of the coronary artery, thus forming a junction at the wall of the coronary artery. Further away from this junction, the vein graft tends to lie against the heart structure, or substantially parallel to the lumen of the coronary artery. The transition of the vein graft from a substantially perpendicular juncture to the coronary artery to a substantially parallel position with respect to the coronary artery wall often occurs abruptly, which may result in kinking of the vein graft, with possibly reduced blood flow.
Third, joining vessels having relatively small diameters (e.g., 1-4 mm) presents the additional consideration of keeping the vessels open after the anastomosis has been made. It is therefore helpful to provide the anastomosis with a diameter equal to or larger than the diameter of the smaller vessel being joined. This larger anastomosis is performed in order to minimize the risk of closing off the flow due to the natural healing response. However, it is a challenge to provide a delivery system which is compatible with the dimensions of the anastomosis.
In view of the foregoing, it is an object of this invention to provide apparatus that can be used to make anastomotic connections in lieu of manual suturing.
It is another object of the invention to provide apparatus that can be used to make anastomotic connections even though access to the site of the anastomosis may be limited or even only indirect or remote.
It is still another object of the invention to provide apparatus that can be used to make anastomotic connections without the need for a high degree of manual suturing skill.
It is yet another object of the invention to provide apparatus for making anastomotic connections that is less adversely affected than manual suturing by adjacent or nearby body motion (e.g., motion of the patient's heart).
It is a further object of this invention to provide apparatus for facilitating the making of higher quality anastomotic connections more rapidly and with more consistent results than is possible with prior art methods and apparatus such as manual suturing.
It is another object of the invention to provide apparatus for making a high quality anastomotic connection when joining two conduits having different diameters.
It is another object of the invention to provide apparatus for making a high quality anastomotic connection when joining two conduits having relatively small diameters.
It is another object of the invention to provide apparatus for making high quality anastomosis which allows the conduits to be positioned in a substantially parallel configuration with respect to one another and which prevents kinking of the conduits.